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G. W. GOY.

TELEPHONE EXCHANGE SWITCH APPARATUS. No. 260,667. 4 Patented July 4, 1882.

INVENTUF UNITED STATES PATENT OFFICE.

GEORGE W. COY,.OF MILFORD, CONNECTICUT, ASSIGNOR OF TWO-THIRDS TO JAMES Gr- SMITH OF HACKENSACK, NEW JERSEY, AND CHARLES E. BUELL,VOF WASHINGTON, DISTRICT OF COLUMBIA.

TELEPHONE-EXCHANGE SWITCH APPARATUS.

SPECIFICATION forming part of Letters Patent No. 260,667, dated July 4, 1882.

Application filed February 23, 1882. (No model.)

To all whom it may concern;

Be it known that I, GEO. W. COY, of Milford, in the county of New Haven and State of Connecticut,have invented certain new and useful Improvements in Telephone-Exchange Switch Apparatus, of which the following is a specification.

My invention consists of certain novel and simplified combinations of apparatus for signaling to either or both of two subscribers after their lines have been connected, and for allowing the central-office operator to ascertain', either by interposing a telephone without breaking the connected lines or by the aid of a disconnecting-annunciator, whether or not conversation has ceased.

The nature of my invention will be readily understood from the accompanying drawings and description, and will be particularly defined in the claims hereto annexed.

Figure 1 is a diagram of a central-office switch-board and apparatus embodying my invention. Fig. 2 is a modification showing an arrangement whereby eitherof two connected subscribers may be'signaled without signalin g the other;

Referring to Fig. 1, A represents a portion of a central-office switch-board, of any desired construction, adapted to connect any two'ot' the line strips or platesto which the several subscribers wires are connected.

The subscribers lines are indicated at a a a, 8210., while B B B, &c., are annunciators forindicating to the central-ofiice operator the line from which a call comes.

The devices whereby the line-strips are connected for placing subscribers in communication are here shown as horizontal rows of pivoted switches, each pair of horizontal rows forming the terminals of a local loop, 5, so that when a switch-lever of a row connected to one end of the loop is placed upon one line-strip and a lever of a row connected to the other end upon another line-strip the two line-strips willbe electrically connected through the loop.

It is obvious thatother forms of switch deceased, while the calling-keyH allows the central-office operator to ring a subscribers bell after the lines are connected by short-circuiting battery F, or in any other suitable manner controlling the flow of the current from the battery to the connected lines. Each mainline circuit is normally to ground through one of a series of switches, f, which should be normally connected to thestuds leading 'to'the main-line batteries M B,or to a single battery for all the lines and to earth. These switches f may be turned to connect a main line to a wire, 7, leading to a circuit-shifting apparatus, L, which in its normal position completes the circuit of 7 to earth through its upperstop and the'telephone apparatus M, and which maybe shifted to break the latter circuit and close a circuit leading to a main battery, M B, or other suitable generator or apparatus for sending currents to line to operate the subscribers bells.

Battery M B may, if desired, be used in the usual operations of signaling to a subscriber called for, although I design ordinarily employ'ingfor this purpose the calling-keys placed in connection with loops 5, and reserving the generator M B for use only when it is desired to hold conversation between the central office and a subscribers station, and it is necessary for the central cities to call that station.

The operation is as follows: Normally each line is connected, as usual, to earth through the maindin'e Iannunciator B and the mainline battery M 13. Upon receiving acall from a line the centraloffice operator connects that line to the telephone apparatus M by op erating a switch of the construction shown, or of any other construction snitable for the purpose, and, upon learning the name or number of the subscriber or line wanted, immediately connects the two lines through a loop, 5, and the apparatus contained therein in the manner before described, and disconnects the line called from its eartlrconnection by means of its switch f. He then operates the calling key L1 apparatus H any number of times, thus causing the bell of the subscriber called for to ring by the alternate flow and withdrawal of the current from the lines, and leaves the two connected subscribers to begin conversa tion. The bell of the subscriber from whom the call is first received is not ad'ected, having been placed out of connection with the linein the ordinary way by the act of taking up the telephone. As will be observed, the act of withdrawing the battery F from line by key H does not affect the annunciator d, since the battery F continues to. flow through the annunciator, and the key H, being a continuitypreserring key, as indicated, does not interrupt the tiow of the battery. When the subscribers have finished their conversation they cause an interruption of the circuit, either automatically through the action of the switch apparatus when operated to restore the subscribers instruments to their normal condition, or through any other suitable devices in a well known manner, thus interrupting the flow of battery-current from F and operating annunciator d, which is suitably constructed for this purpose.

At any time during conversation between subscribers, or immediately after connecting their lines and before conversation begins, the central-oftice operator may, by means of spring-jack G, insert the telephone apparatus M without interrupting the circuit, for the purpose of listening or to communicate with the subscribers.

Fig. 2 represents a modified arrangement of calling-keys in the loop and of the calling-battery. In this arrangement the calling-battery isconnected to groundandto thelowercontacts of two calling-keys, N N, placed in the loop 5, and so connected that their upper contacts form a portion of the loop-circuit. If, when two lines are connected, one of said keys be operated for the purpose of connecting the calling-battery to the line connected to its side of the loop, the line connected to the other side of the loop, and the key there placed, is dis- I connected, and the battery flows only to the line desired. In this arrangement the disconnectingannunciator must be operated by a current transmitted from the subscribers station. By this arrangement anysubscriber may be called whether his line be connected to another through a loop, 5, or not, it being only necessary to connect the line to one end of the loop and operate the nearest key. The switch L and battery M B could, under this plan, be dispensed with. Instead of the calling-key H, any other suitable device placed in the loop through which the lines are to be connected might be employed, whether acting or not to interrupt the flow of the battery through the annunciator.

The annunciator B might be placed between the disconnecting-switches f and the ground.

My invention is not limited to any details of construction in the various switches, keys, &c., these being well known in the art, and it being perfectly feasible to substitute many other forms for those here shown.

I do not claim the combination, with a telephone switch-board,of a loop containing a spring-jack, telephone apparatus connected to the plug of the spring-jack, and means for con neeting the lines of subscribers to the ends of said loop.

What I claim as my invention is 1. The combination, substantially as (le scribed, with a telephone switch -board, of a. loop containing a signaling-key, and means for connecting any two subscribers lines through said loop and signaling-key.

2. The combination, substantially as described, with a telephone switch board, of a loop containing a signaling-key, means-for con nectingany two subscribers lines through said loop and signaling key, a battery or other suitable generator of electricity, and circuitconnections, as described, whereby the opera tion of the key alternately withdraws and introduces a signaling-current to a main line.

3. The combination, substantially as described, with a telephone central olfice switch= board, of a loop containing an annunciator, battery, and signaling-key, and means for in troducing said loop between anytwo telephone lines.

scribed, with a telephone switch board, of a loop containing a battery and annunciator, means for connecting the subscribers lines for oral communication through said loop and battery, and a short-circuitin g signalingkey for short-circuiting the battery in the loop through the annunciator.

5. The combination, substantially as dc scribed, with two line-connecting strips or wires in a telephone switch-board, of a loop wire the ends of which are connected to said line-strips, and a battery, annunciator, and signaling-key included in said loop.

6. The combination, substantially as described, with two line-connecting strips or wires in a telephone switch-board, of a loopwire the ends of which are connected to said line-strips, and a spring-jack and annunciator included in said loop.

7. The combination, substantially as described, with two line-connecting strips or wires in a telephone switch-board, of a loop 4. The combination, substantially as dc its connected to said line-strips and devices for signaling to a snbscribers station, said del vices being placed in the loop so as to be in lcircuit between the lines connected by said 8. The combination, substantially as described, with two line-connecting strips or wires in a telephone switch board, of a loop connected to the line-'connectingstrips, a battery included in said loop, and a key, also con- 10 nected in the loop, and operating to withdraw the battery from the connected lines.

GEORGE W. OOY. Witnesses:

JAMES T. HIGBY,

SAMUEL E. LOVEJOY. 

